class ActiveSupport::Deprecation::DeprecatedInstanceVariableProxy

Default deprecator is ActiveSupport::Deprecation.
instance variable.
variable via request method and execute the same method on non-proxy
warn method on deprecator_instance and will fetch @_request
When someone execute any method on @request variable this will trigger
end
end
@request
def old_request
end
@_request
def request
end
@_request = :a_request
@request = ActiveSupport::Deprecation::DeprecatedInstanceVariableProxy.new(self, :request, :@request, deprecator)
def initialize(deprecator)
class Example
deprecated instance variable.
This DeprecatedInstanceVariableProxy transforms instance variable to

def initialize(instance, method, var = "@#{method}", deprecator = ActiveSupport::Deprecation.instance) 

def initialize(instance, method, var = "@#{method}", deprecator = ActiveSupport::Deprecation.instance)
  @instance = instance
  @method = method
  @var = var
  @deprecator = deprecator
end

def target 

def target
  @instance.__send__(@method)
end

def warn(callstack, called, args) 

def warn(callstack, called, args)
  @deprecator.warn("#{@var} is deprecated! Call #{@method}.#{called} instead of #{@var}.#{called}. Args: #{args.inspect}", callstack)
end